Aromatic polyamides, also known as aramid polymers or aramids, are well-known in macromolecular and material sciences for their outstanding thermal and mechanical properties. Their properties have been attributed to their amide linkages, shared with conventional aliphatic polyamides, their highly aromatic structure, and the interactions between the polymer chains via highly directional hydrogen bonds.
Commercial aramids as poly(p-phenylene terephtalamide) (PPPT, p-aramid, Kevlar®, Twaron®) and poly(m-phenylene isophthalamide) (PMPI, Nomex®, Teijinconex®) have been available for decades and have been found to be useful in a wide range of high-performance applications.
Known aramid polymers can be processed into flame-resistant, cut-resistant, and high tensile strength synthetic materials, with advanced technological applications in almost all industrial fields.
Recent contributions in the art involve incorporating new chemical functionalities in the polyamide backbone or lateral structure of aramids in order to provide key properties for the expansion of the technological applications of aramids.
WO2008028605A2 describes cross-linked aramid polymers wherein the aramid backbone has been functionalized with arylene carboxylic acid and hydroxyl groups, optionally with an additional cross-linker agent. This document describes the process to cross-link the aramid polymers obtained by thermal treatment forming an ester linkage between the polymer chains, optionally through the addition of a cross-linker agent. WO2008028605A2 is silent about the electric, thermal, mechanical, stability and processing properties of the disclosed cross-linked polymer.
WO2009130244A2 describes aramid polymers which are cross-linked through the amide moiety in the aramid backbone via poly(meth)acrylic acid (PAA) as a cross-linker agent. However, the provided data only shows a slight improvement of the compressive properties of the aramid cross-linked via PAA and remains silent about electric, stability, and other key thermal and mechanical properties as Young's Module and tensile strength.
From what it is known in the art it is derived that there is still the need of finding new aramids with good properties, or combination of properties, to suit the technological needs of the industry, while featuring simple and scalable preparation processes and ease of transformation.